Still don't understand how memory timings affect system performance? Corsair
has an excellent
writeup on this, they really go into detail here!

Memory modules are currently available which support a wide variety of different
speeds and latency settings. Speed is easy to understand - in general, faster
is better. But what do the latency settings mean? And, what impact do they have
on memory performance? This paper will provide a brief background on latency
settings and what they mean. Then, we will move to the lab, where we will run
a suite of benchmarks over a wide variety of latency settings, and we will measure
the impact of these settings on benchmark scores.